Muscle Fiber Recruitment
Every day you use muscle fibers. The muscle fibers that you use are developed, and the muscle fibers that you don’t use never undergo hypertrophy and grow bigger. Put an arm or a leg into a cast to completely immobilize it, and you’ll find that when the cast comes off, the muscles have shrunk from disuse. Of course the opposite is true. If you use muscle fibers that haven’t been used, they will either grow in size, strength, or endurance. This being true, one of the goals of weight training should be to recruit muscle fibers during workouts.
3 Ways to Recruit More Muscle Fibers
There are at least three ways to increase or maximize the amount of muscle fibers used during exercise.
1. Add More Weight
One way to recruit more muscle fibers is to add more weight to an exercise. Ed Coan, Kirk karwoski, Doug Furnas are masters of incrementally adding weight from one week to the next. These old school powerlifters rarely if ever missed lifts in their workouts or competition. Furnas hits a 970 squat and makes it look easy in the video below and squats over 700 for 5 reps.
Drawbacks:
If you are depending on the weight alone as the source to recruit more muscle fibers, you will end up needing to use very heavy weights in order to maximize muscle fiber recruitment. This can be hard on your joints, connective tissue and your nervous system. An alternative is to lift moderately heavy weights while pushing to failure, or to lift moderately heavy weights with maximum explosive force. (This form of training will be emphasized in the next article Muscle Fiber Recruitment part 2).
2. Add More Reps or Push Farther into a Set
A second way to increase the amount of muscle fibers that are recruited during exercise is to add reps to your set. I recommend stopping at your marker rep, but others advise training to failure or beyond to recruit the maximum number of muscle fibers. As muscle fibers tire from the beginning of the set, new muscle fibers will be recruited to enable a lifter to continue lifting until they can’t lift any more. Bodybuilders are more likely to use this method than powerlifters. The following video is an example of pushing a set beyond the point of failure with forced reps and rest pause reps.
Drawbacks
The lifter in the video is strong for his size. Other lifters and body builders have become exceedingly strong using this type of training. This being the case, I would never say that training to failure is wrong for everyone or that it has no value in every case. However, there are lifters who will find that training to failure crosses over into endurance training which can create a compromise between a strength adaptation and an endurance adaptation. Training to failure can also be hard on your central nervous system and shut down the willingness of your body to progressively grow stronger over a long period of time. This is a problem for the average person which is why I recommend stopping a set when the pace of reps starts to slows down at the end of a set (which is a precision point training concept). However, a person with a highly anabolic physiology may find that training to failure is an optimum way to train.
3. Lift with More Force
The third way that to increase the amount of muscle fibers used during exercise is to increase the amount of force that is used when lifting a given weight. I believe more people would benefit from using this as the primary means of improvement before reps and weight are added and this will be discussed fully in the next article (click here for Muscle Fiber Recruitment Part 2). Until then, best of training to you.